Infeed method and mechanism for book-sewing machine

ABSTRACT

An infeed method and mechanism for feeding signatures in succession to a Smyth book-sewing machine. According to the invention, the signatures are stacked in a hopper from which they are extracted in succession by a transfer means. This transfer means grips each signature along its folded edge and transfers the signature to gripping means on an infeed carriage. The carriage transports each signature edgewise in a generally vertical attitude with its folded edge uppermost past a signature-parting shoe, which spreads the center signature pages, to a terminal position over the sewing machine saddle where the signature is released to drop onto the saddle. A malfunction detector is provided to shut down the infeed mechanism in response to failure of the mechanism to deposit a signature on the saddle or improper placement of a signature on the saddle.

[72] Inventors Jack M. Hilliard P.O. Box 83, Tioga, Tex. 76271; William W. Tingle, 1215 Queen Ann Court, Glendorn, Calif. 9l740 [2]] Appl. No. 795,962 [22] Filed Feb. 3, I969 [45] Patented Aug. 24, I971 [54] INFIEED METHOD AND MECHANISM FOR BOOK- SEWING MACHINE 16 Claims, 12 Drawing Figs.

[52] US. Cl 270/54, 270/58 [SI] Int. Cl B65h 39/02 [50] Field of Search 270/54, 55, 57

[56] References Cited UNITED STATES PATENTS 1,829,833 11/1931 Kast 270/55 Assistant Examiner-L. R. Oremland Attorney-Boniard I. Brown ABSTRACT: An infeed method and mechanism for feeding signatures in succession to a Smyth book-sewing machine. According to the invention, the signatures are stacked in a hopper from which they are extracted in succession by a transfer means. This transfer means grips each signature along its folded edge and transfers the signature to gripping means on an infeed carriage. The carriage transports each signature edgewise in a generally vertical attitude with its folded edge uppermost past a signature-parting shoe, which spreads the center signature pages, to a terminal position over the sewing machine saddle where the signature is released to drop onto the saddle. A malfunction detector is provided to shut down the infeed mechanism in response to failure of the mechanism to deposit a signature on the saddle or improper placement of a signature on the saddle.

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BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates generally to the book binding art and more particularly to a method of and an infeed mechanism for feeding signatures in succession to the saddle of a Smyth book-sewing machine.

2. Prior Art Generally speaking, the production of a book involves initial printing of the book contents on large sheets each of which provides several pages of the finished book. Each sheet is then folded a number of times to form a section or signature. This signature consists of several overlying printed sheet portions which constitute the pages of the finished book. The signatures are fed to a book-sewing machine which sews the signatures together along their folded edges and applies paste to the next to the last or final edges. Thereafter, a cover is applied to the assembled signatures to provide the finished book.

Two different book sewing techniques are employed. These techniques are commonly referred to as side sewing and Smyth sewing. In side sewing, the sewing needles pass through the folded edges of the signatures in directions normal to the signature pages. In Smyth sewing, the needles pass through the signature folds generally parallel to the signature pages in such a way as to form loops. Thread is then passed through the loops of the several signatures to join the latter in assembled relation. The present invention is concerned with this latter book sewing technique and particularly with the Smyth'sewing machines which are employed to practice the technique.

Generally speaking, a Smyth book-sewing machine is characterized by a saddle on which are placed, in succession, the signatures to be assembled into a'book and from which the signatures are fed into the machine. This saddle has a pair of saddle feed plates which converge in the direction of their upper edges to provide the saddle with a generally inverted V configuration in vertical section. Movable between and in the lengthwise direction of the upper feed plate edges is a signature pusher for feeding each signature along the saddle into the sewing machine.

Briefly in operation of the book-sewing machine, the signatures are deposited in succession on the saddle in such a way that the latter enters between the two center pages of the signature and the folded signature edge is situated along the upper edges of the saddle feed plates. The signature pusher, which is retracted away from the machine during placement of each signature on the saddle, is then driven toward the machine through an infeed stroke. In the course of this infeed stroke, the pusher engages the signature currently on the saddle and advances the signature into the sewing machine. The pusher is then retracted to receive the next signature.

The existing Smyth book-sewing machines employ an infeed mechanism for delivering the signatures in succession to the machine saddle in the proper timed relation to the reciprocating motion of the signature pusher. These existing infeed mechanisms, however, are characterized by certain deficiencies, notably excessive complexity and set up time, which the present invention seeks to avoid.

SUMMARY OF THE INVENTION The present invention provides an improved method of and infeed mechanism forfeeding signatures in succession from a hopper to the saddle of a Smyth book-sewing machine. Generally speaking, the present signature infeed method involves extraction of the signatures in succession from the hopper and transportation of each signature to the sewing machine saddle by gripping the signature along its folded edge and moving the signature edgewise in a generally vertical attitude, with its folded edge uppermost, to a terminal position over the saddle. During its edgewise movement toward the saddle, the center pages of the signature are parted by the wedging action of a signature-parting shoe, or divider, to receive therebetween the sewing machine saddle. Upon arrival in its terminal position over the saddle, each signature is released to drop by gravity onto the saddle.

The present infeed mechanism is designed to carry out the above infeed method automatically at high speed. To this end, the infeed mechanism is equipped with signature transfer means and signature infeed meanseach having signaturegripping means. The transfer means and infeed means are driven in synchronism in such a way that the transfer means periodically withdraws a signature from the signature hopper and transfers the signature to the infeed means. The infeed means grips each signature along its folded edge to hold the signature in a vertical attitude with its folded edge uppermost. Immediately after transfer of each signature to the infeed means, the latter means is actuated to transport the signature edgewise to its terminal position over the sewing machine saddle.

Situated within the path of infeed movement of each signature with the infeed means is a signature divider or parting shoe over which the signature passes. This parting shoe is tapered to enter between the center sheets or pages of the signature and thereby spread the two halves'of the signature to receive therebetween the sewing machine saddle. Upon arrival at its terminal position over the saddle, the infeed gripping means are opened to release the signature for dropping onto the saddle. The infeed means is then returned to its original position to receive the next signature from the hopper.

The infeed mechanism also embodies a malfunction detector. This detector is operative to sense and shut down the infeed mechanism in response to two different conditions of malfunction. One of these conditions involves failure of the infeedmeans to deposit a signature on the sewing machine saddle at the conclusion of each infeed stroke of the infeed means. The other malfunction condition involves improper placement of a signature on the saddle. Also embodied in the infeed mechanism are novel pneumatic means for aiding withdrawal of the signatures from the hopper by the transfer means and entrance of the signature parting shoe between the center signature pages.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevation of a present signature infeed mechanism installed on a Smyth book-sewing machine;

FIG. 2 is an enlarged top plan view looking in the direction of the arrows on line 2-2 in FIG. 1;

FIG. 3 is an enlarged section taken on line 33 in FIG. 1;

FIG. 4 is an enlarged section taken on line 44 in FIG. 3;

FIG. 5 is an enlarged section taken on line 5-5 in FIG. 1;

FIG. 6 is an enlarged section taken on line 6-6 in FIG. 5;

FIG. 7 is an enlarged section taken on line 77 in FIG. 5;

FIG. 8 is an enlargement of the area encircled by the arrow 8 in FIG. 1;

FIG. 9 is an enlarged fragmentary view of the backup plate, lip guide and related features of FIGS. 1 and 2, which features are utilized in spreading signatures;

FIG. 10 is a sectional view taken at line l0l0 in FIG. 9', and

FIGS. 11 and 12 are sectional views taken at line II-ll and line 12-12 in FIG. 9, showing successive stages in the separation of a signature.

DESCRIPTION OF THE PREFERRED EMBODIMENT Movable along a slot 20 between the upper edges of the feed plates is a signature pusher 22. Pusher 22 is connected, through a feed connecting rod 24, to an oscillatory saddle feed bellcrank 26. During operation of the sewing machine, this bellcrank is driven in oscillation to reciprocate the signature pusher 22 along its slot 20. The pusher projects a distance above the upper saddle feed plate edges during its feed stroke, as shown in FIG. 1.

FIGS. 9 through 12 show, in edge view, a typical signature S to be stitched in the sewing machine 12. The signature is composed of a number of interleaved folded pages having folds along one edge of the signature so as to provide the latter with a folded edge F. The pages at one side of this fold provides a first group of pages P The pages at the opposite side of the fold provide a second group of pages P It is significant to note here that the width of the page group P normal to the folded edge F, is slightly greater than the corresponding width of the page group P Accordingly, the outer edge of the page group P projects-slightly beyond the outer edge of the page group P to provide a lip L. A

Briefly in operation of the book-sewing machine 12, the signatures S are placed in succession on the machine saddle 16 in such a way that the upper tapered edge of the saddle enters between the two page groups P,, P of each signature. The folded edge F of each signature extends above the upper edge of the saddle, and the two page groups of the signature extend downwardly in diverging relation across the saddle feed plates 18. The signatures are placed on the saddle in timed relation to thereciprocating motion of the signature pusher 22 so that the latter is extended to its position of FIG. 1 when the saddle receives a signature. The pusher then proceeds throughits infeed stroke. In the course of this stroke, the pusher engages the signature currently on the saddle and advances this signature to the left in FIG. 1 and into the book-sewing machine.

The present infeed mechanism is designed to deliver signatures S in succession to the sewing machine saddle 16in the manner explained. In general terms, 'the infeed mechanism has a hopper 28 for containing a supply stack 30 of signatures, and signature-handling means 32 for transporting the signatures in succession from the hopper to a terminal position over the sewing machine saddle 16. In the course-of its transport movement from the hopper to the saddle, each signature S is gripped along its folded edge F and held with this edge uppermost, such that the page groups P,, P of the signature hang freely in a generally vertical attitude. Each signature is moved edgewise in this vertical attitude toward the sewing machine saddle l6.

Situated in the path of edgewise movement of each signature toward the sewing machine saddle 16 is a signature divider or parting shoe 34. This parting shoe enters between and parts or spreads the two page groups P P of the signature as the latter approaches the saddle so as to permit entrance of the saddle between the page groups. .In the terminal position of each signature S, the latter is suspended over the saddle with the upper tapered portion of the saddle protruding upwardly between the signature page groups P P Each signature, when in this terminal position, is released to drop onto the saddle.

The operation of the infeed mechanism 10 is timed with the operation of the book sewing machine 12 so that each signature S is delivered to the sewing machine saddle 16 when the signature pusher 22 is extended. The pusher is then driven through its infeed stroke to advance the signature into the sewing machine.

Embodied in the infeed mechanism 10 are malfunction detection means 36. This detection means is operative to sense two different malfunction conditions and to terminate operation of the infeed mechanism in response to either condition. One of these conditions of malfunction involves failure of the infeed mechanism to deliver a signature S to the sewing machine saddle during the infeed portion of its operating cycle. The other malfunction condition involves improper placement ofa signature on the saddle.

The signature handling means 32 of the infeed mechanism includes a transfer means 38 and an infeed means 40. The infeed means 40 is equipped with signature-gripping means 42 for gripping each signature S along its folded edge F and holding the latter in a generally vertical attitude referred to earlier. The infeed means is movable between a signature-receiving position adjacent the hopper 28 and a signature-releasing position adjacent the sewing machine saddle 16. Transfer means 38 operates to transfer the signatures S in succession from the hopper 28 to the gripping means 42 on the infeed means 40 when the latter occupies its signature-receiving position. During subsequent movement to its signature releasing position, the infeed means 40 transports the signature to its 1 terminal position, where the signature is released to drop onto the sewing machine saddle. The infeed means is then returned to its signature-receiving position to receive the next signature S from the hopper 28.

Referring now in greater detail to the embodiment of the invention which has been selected for illustration, the infeed mechanism 10 has a frame 44. The signature hopper 28 is situated at the front side of this frame, adjacent the end of the frame remote from the sewing machine 12. Hopper 28 has a bottom plate 46, sidewalls 48 rising from the plate, a front adjustable guide 50 secured to the front end of the plate 46, and rear guides 52. These are adjustable to accommodate the hopper to receive signatures of various sizes. Turning to FIG. 3, it will be seen that the guides 52 are located some distance to the rear of the rear edge of the hopper plate 46. The rear edge of this plate and the rear guides defined therebetween an exit opening 54 through which the signatures are withdrawn from the hopper, in the manner to be explained presently. The hopper is open at its top to permit placement of signatures in the hopper. Referring to FIG. 1, it will be seen that the front guide 50 is relatively narrow and situated midway between the hopper sidewalls 48 so as to define intervening openings. These openings facilitate placement of a signature stack within and removal of the stack from the hopper. It will also be observed in FIG. 1 that the hopper 28 is located approximately at the same level as the sewing machine saddle 16.

The signature transfer means 38 will now be described in detail by particular reference to FIGS. 3 and 4. Situated to the rear of the rear hopper guides 52, a distance above the bottom plate 46 of the hopper, is a rocker shaft 56. The ends of this shaft are rotatably supported in bearings on the hopper sidewalls 48. Fixed to the rocker shaft 56 are a pair of transfer arms 58. Transfer arms 58 are rotatable between their full line and broken line positions of FIG. 3. In the ensuing description, the full line positions of the transfer arms will be referred to as their signature-gripping positions or simply their gripping positions. The broken line positions of the arms will be referred to as their signature releasing positions or simply releasing positions. The outer extremity of each gripping arm 58 turns laterally to form a fixed signature-gripping jaw 60. As shown in FIG. 3, the fixed gripping jaws 60 extend forwardly into the hopper exit opening 54 when the transfer arms occupy their signature-gripping positions. Pivotally mounted intermediate its ends on the outer end of each transfer arm 58 is a movable gripping jaw 62. Each movable gripping jaw is rotatable relative to its respective fixed gripping jaw 60 between a closed signature-gripping position and an open signature-releasing position.

Operatively connected to the movable gripping jaws 62 are operating means 64 for rocking the jaws between their open and closed positions in timed relation to rotation of the transfer arms 58 between their gripping and releasing positions. Jaw-operating means 64 comprise a bellcrank 66 pivoted on the rear side of each transfer arm 58 about midway between the rocker shaft 56 and the fixed jaw 60 of the arm. A link 68 is connected between one arm of the bellcrank and the rear end of the movable jaw 62 on the transfer arm. Connected to the other arm of each bellcrank is a link 70. Link 70 is a telescoping link with end flanges 70a and a compression spring 70b mounted between the flanges to provide an extending force to the link. The upper end of this link is attached to the rear end of a lever 72 which is pivoted at 72a on the transfer arm adjacent the rocker shaft 56. Located midway betweenthe two transfer arm levers 72 is a cam follower 74.

This cam follower rides ona cam 76 which encircles the rocker shaft 56 between the transfer arms 58 but does not rotate with the shaft. Cam 76. is attached at 78 to a bracket 80 which slides on rods 82 fixed to the frame 44 so as to permit alignment of the cam with the cam roller 74. The bracket and hence the cam are locked in adjusted position by tightening the bolt 780.

The gripping-jaw-operating means 64 described to this point are so constructed and arranged that the cam roller 74 rides back and forth along the cam 76 during swinging of the transfer arms 58 between their full line signature-gripping positions and broken line signature releasing positions of FIG.

3. This produces a camming action on the cam levers 72 which rocks these levers on their pivot axes. The cam 76 has a profile such that levers 72 are rotated in a direction to compress the transfer arm springs 70b during forward swinging of the transfer arms to signature-gripping position. During rearward swinging of the transfer arms to signature-releasing position, the rear ends of the levers 72 are allowed to rotate in the op posite direction and thereby reducethe compression in the springs 7 0b.

The bellcrank linkagemeans 66, 68, and 70 which operatively connects the cam levers 72 to their signature-gripping jaws 62 form toggle mechanisms having toggle pivots a and b. As explained below, these toggles are locked in jaw open position at the rear ends of the rearward signature transfer strokes of the transfer arms 58; The toggles are unlocked to allow closure of the signature-gripping jaws 62 by the action of their springs 70b at the forward ends of the transfer arm return strokes.

Fixed to each transfer arm bellcrank 66 on its pivot axis is a sleeve 84. Sleeve 84 projects inwardly toward the opposite transfer arm 58. The two bellcrank sleeves 84 are journaled on a common shaft 84a which is fixed at its ends to brackets 84b fixed to the transfer arms 58. The inner ends of sleeves 84 mount arms 86 which function as toggle setting and releasing arms. Located in the path of rearward swinging movement of the toggle arms 86 with the transfer arms 58 is an abutment or stop 88. This abutment is situated to engage the toggle anns 86 upon arrival of the transfer arms in signature-releasing position and to rotate the toggle arms in a direction to open the transfer arm gripping jaws 62 against the action of the jaw springs 70b to a position wherein the toggle pivots b move past dead center position relative to the toggle pivots a so as to lock the gripping jaws in open position. During the subsequent for ward return stroke of the transfer arms to signature gripping position, the gripping jaw springs 70 b are compressed, as just described, while the gripping jaws 62 remain locked in open position. Located in the path of forward swinging movement of the toggle arms 86 with the transfer arms 58 is an abutment or stop 88! which engages the toggle arms upon arrival of the transfer arms in signature-gripping position. Stop 88! rotates the toggle arms 86 in a direction to rotate the bellcranks 66 back through dead center position and thereby unlock the gripping jaws 62 for closing under'the action of the now compressed jaw springs 70a. When the signature transfer arms 58 are in their forward signature-gripping positions, these springs are compressed to-close. the jaws with sufficient force to extract the lower signature from the hopper 28 against the resisting force exerted onthe lower signature by the stack of signatures within the hopper. During following rearward swinging.

of the transfer arms to signaturereleasing position, the compression in the jaw. springs is relieved by the cam 76, in the manner explained above, to reduce the spring closing force on the gripping jaws 62 soas to permit transfer of the signature tothe infeed carri'ag'was explained below. 1

The transfer arrns'58 are rotated between their drive means 90. These drive means comprise an arm 92 fixed to one end of the rock shaft 56. Pivoted at one end of the frame 44 adjacent the arm 92 is a lever 94. The free ends of arm 92 and lever 94 are connected by a link 96. Attached at its upper end to the lever 94, adjacent the outer end of the lever, is a connecting rod 98. The lower end of this rod connects to a crank arm 100 on a fly wheel 102 which is rotatably supported on the frame 44. Fly wheel 102 is driven from a power takeoff sprocket 104 on the book-sewing machine 12 through a sprocket chain 106.

It is now evident that rotation of the fly wheel 102 oscillates the transfer arms 58 through their solid line gripping and broken line releasing positions of FIG. 3. Upon arrival of the arms in signature-gripping position, the then open gripping jaws 60, 62 are released to close by spring pressure, as just explained. When in this gripping position, the signature-gripping jaws project forwardly intothe hopper exit opening 54 so that when released, the jaws close about the folded edge F of the lowermost, signature S in the hopper. .During subsequent swinging of the transfer arms to releasing position, the jaws withdraw the signature from the hopper and transfer the signature to the infeed means 40, as explained below.

Referring to FIG. 3, it will be seen that the transfer arm gripping jaws 60, 62 when in forward signature gripping position within the hopper exit opening 54, are located a distance below the level of the lowermost signature in the hopper 28. Accordingly, it is necessary to pull down the adjacent edge of the lower signature, as shown in FIG. 3, so that the edge may enter between the gripping jaws on the transfer an'ns as the latter approach their signature-gripping positions. It is significant to note here that the signatures S are stacked in the hopper with their folded edges F to the right over the exit opening 54. Accordingly, it is the folded edge of the lower signature which is deflected downwardly in FIG. 3.

In order to thus bend down the folded edge F of the lowermost signature S in the hopper 28 as the transfer arms 56 swing forwardly to gripping position, the infeed mechanism 10 is equipped with a pneumatic signature pull down device 108. This pulldown device comprises a support which extends across the under side of the hopper exit opening 54 and is pivotally mounted on the hopper at 112 for vertical swinging movement toward and away from the opening. The support is connected to the transfer arm rocking lever 94 through a link 114. Accordingly, the support is oscillated vertically in unison with oscillation of the transfer arms 58 between their signature gripping and releasing positions. In this regard, it will be observed that the support 1 10 rotates downwardly away from the hopper exit opening 54 as the transfer arms 58 rotate forwardly to gripping position and upwardly toward the exit opening as the arms rotate rearwardly away from the gripping position.

Mounted on the oscillating support 110, midway between the ends of the hopper exit opening 54, are two suction cups 116. These suction cups are connected through a vacuum hose 118 to a vacuum unit 120 on the frame 44. This vacuum unit has a valve 122 operated by a cam 124 on the fly wheel shaft 126. During operation of the transfer means 38, the oscillating support 110 rotates upwardly to engage the suction cups 116 with the under side of the folded edge F of the lowermost signature S in the hopper 28 as the transfer arms 58 swing rearwardly to their signature releasing positions. Simultaneously, the cam 124 opens the vacuum valve 122 to connect the suction cups 1 16 to the vacuum unit 120. This creates a suction in the cups which causes the folded edge of the lower signature to adhere to the cups. During subsequent forward return of the transfer arms 58 to their solid line gripping positions of FIG. 3, the support 110 and its suction cups 116 are rotated downwardly to their positions of FIG. 3. The parts are signaturegripping and signature-releasing positions by transfer arm so constructed and arranged that the folded edge F of the lower signature, which then adheres by suction to the suction cups, is located in the proper position to enter between the then open signature-gripping jaws 60, 62 on the transfer arms 58. Immediately after the open jaws move over the lower signature, the gripping jaws are released to close and grip the signature by the earlier described action of the jaw-operating means 64. At the same time the vacuum valve 122 is then reclosed by its operating cam 124 to release the grip of the suction cups on the signature.

At this point, the transfer arms 58 commence their rearward transfer stroke. The gripping jaws 60, 62, which are presently closed to grip the lower signature S in the hopper 28, pull the signature, folded edge first, from the hopper through its exit opening 54. In the course of the rearward swinging stroke of the transfer arms, the gripping jaws 60, 62, and hence the signature S gripped by the jaws, swing rearwardly and upwardly along an arcuate path to the final broken line signature releasing position of FIG. 3. As the arms approach this position, the gripping jaws 60, 62 release the signature by the earlier described action of the jaw-operating means 64.

It will be recalled that the transfer means 38 operates to transfer signatures S in succession from the hopper 28 to the infeed means 40. This infeed means comprisesan infeed carriage 128 slidably supported on rails or rods 130 on the machine frame 44. Rods 130 extend along the rear side of the sewing machine saddle 16, just above the upper tapered edge of the saddle, and from the saddle to a position opposite the rear of the signature hopper 28.

infeed carriage 128 is driven back and forth along the rods 130, between a signature-receiving position illustrated in broken lines in FIG. 2 and a signature-releasing position illustrated in solid lines in FIG. 2, by a carriage drive means 132. This carriage drive means comprise a drive arm 134 pivoted at its lower end on the frame 44. The upper end of the drive arm is attached to the carriage 128 by a-hinged link 136. Also pivoted on the frame 44, to the left of the drive arm 134 in FIG. 1, is an arm 138 which parallels the drive arm. The upper end of arm 138 is connected to the drive arm by a horizontal link 140 to form with the arms and frame a parallel linkage mechanism. Connected between the upper end of arm 138 and a fly wheel 142 on the rear end of the fly wheel shaft 126 is a connecting rod 144.

It is now evident that rotation of the fly wheel shaft 126 from the power takeoff sprocket 104 on the book-sewing machine 12 oscillates the infeed carriage drive arm 134. The signature infeed carriage 128 is thereby reciprocated along its supporting rails 130 between its signature-receiving and signature-releasing positions of FIG. 2 in timed relation to oscillation of the signature transfer arms 58 between their signature gripping and releasing positions of FIG. 3. The carriage drive means 132 is so constructed and arranged that the infeed carriage 128 is arrested or dwells momentarily in its signaturereceiving position concurrently with rotation of the transfer arms 58 to their signature-releasing positions.

Mounted on the infeed carriage 128 is a gripping jaw structure 146. This jaw structure forms part of the infeed gripping means 42 referred to earlier. The jaw structure includes fixed jaws 148 along the front edge of the carriage and pivoted jaws 150 outboard or forwardly of the fixed jaws. The pivoted gripping jaws 150 are spring loaded toward the flxed jaws 148 to closed positions and, as shown in FIG. 3, have a generally bellcrank shape. This bellcrank shape provides the pivoted jaws with upper rearwardly directed arms 152. Pivoted between its ends on the top of the infeed carriage 128 are two carriage jaw release levers 156. The front ends of these levers carry thrust pins 158 which seats against the upper surface of the gripping jaws. Also pivoted on top of the infeed carriage 128 are two release-lever-operating cams 160. Cams 160 are fixed to and interconnected by a shaft 161 which is joumaled at its ends in brackets 1610 on the carriage. Fixed to the center of shaft 161 is a cam follower 162. Cams 160 engage under the rear ends of the jaw release levers so that counterclockwise rotation of the cams in FIG. 3 rotates the levers in directions to open their gripping jaws 150.

From the preceding description, it is evident that the pivoted carriage gripping jaws 150 are normally retained in their closed gripping positions by their jaw springs. Counterclockwise rotation of the jaw-release-lever-operating earns 160 in FIG. 3 rotates the front ends of the jaw release levers downwardly-against the jaw arms 152 and thereby rotates the carriage jaws 150 to open position against spring action.

According to the present invention, the carriage jaws 150 are released to assume their closed positions by spring action at all times except when the carriage 128 occupies its signature-releasing position. As the carriage approaches this position during each infeed stroke, the jaws 150 are opened. To this end, there is mounted on the left-hand end of the infeed frame 44 in FIGS. 1 and 2 a jaw-opening cam 164. This cam has a beveled cam surface 166 (FIG. 2) located in the path of the lever release cam follower 162. During the terminal portion of each infeed stroke of the infeed carriage 128, the follower 162 engages the cam surface 166 and is thereby cammed forwardly (i.e., to'the left in FIG. 3) to open the pivoted infeed carriage gripping jaws 150.

When the infeed carriage 128 occupies its signature-receiving position shown in broken lines in FIG. 2, the carriage gripping jaws 148, 150 are located at opposite sides of the arcuate path of swinging movement of the signature transfer arms 58. Moreover, the carriage jaws are then situated relative 'to the arcuate path of the transfer arm gripping jaws 60, 62 in such a way that the folded edge F of a signature S held between the latter jaws enters upwardly between the carriage jaws as the transfer arms approach their signature-releasing positions. The transfer arm gripping-jaw-operating means 64 are arranged to open the transfer an'n jaws just after the folded signature edge bottoms out between the carriage jaws. At this point the pressure of jaws 62 on the signature is relaxed (due to action of cam 76 allowing the springs to expand) enough to allow the signature to slip out as it bottoms out in the carriage jaws. This action is timed so that the signature is transferred from the gripping jaws on the transfer arms into gripping position between the gripping jaws on the infeed carriage. After releasing the signature, the transfer arms continue their upward swinging movement to a position above the carriage jaws. In this position, the arms permit unrestricted infeed movement of the infeed carriage to its solid line signaturereleasing position of FIG. 2. It will be understood that the swinging motion of the transfer anns and the reciprocating motion of the infeed carriage are so timed that the carriage commences its infeed stroke while the arms are elevated to clear the carriage. The arms then swing down to grip the next signature in the hopper 28 while the carriage completes the infeed stroke and returns to signature receiving position. Thereafter, the arms again swing upwardly to draw the next signature from the hopper and transfer the signature to the infeed carriage upon return of the latter to signature-receiving position.

At this point, it is evident that during normal operation of the infeed mechanism 10, a signature S is transferred from the hopper 28 to the infeed carriage 128 each time the latter is driven to its signature-receiving position. The carriage is then driven to its signature-releasing position wherein the signature on the carriage is situated in terminal position over the sewing machine saddle 16. As the carriage approaches its signaturereleasing position, the carriage cam follower 162 engages the jaw opening cam 164 which rotates the follower in a direction to open the carriage jaws 150 and thereby release a signature to drop by gravity onto the saddle.

It will be recalled that a signature-parting shoe 34 is situated in the path of infeed movement of each signature S with the carriage 128. This parting shoe comprises an upper guide 168, a lower guide 170, and a splitter 172. The upper guide and A lower guide are attached to the front side of a vertical plate flange 176. Flange 178 extends parallel to the direction of movement of the infeed carriage 128 from a position in advance of the upper guide flange 176 to a position following the latter flange. The leading end of the lower guide flange 178 is turned out to provide a lead in lip 180. Referring to FIG. 10, it will be observed that the lower guide flange 180 is vertically situated so that its upper edge is located at an elevation slightly higher than the rear lower edge of a signature S on the infeed carriage 128 and slightly lower than the front lower edge of the signature. The splitter 172 comprises a plate which extends from the trailing end of the lower guide flange 168 to the leading end of the sewing machine saddle 16. It will be observed that the leading end of the saddle is tapered, in somewhat prowlike fashion, to a leading edge 16a. The splitter plate 172 is disposed in a plane inclined to both the horizontal and vertical and extends from the lower guide flange 178 to the leading end of the saddle and joins to this leading end at the forward side of its leading edge 16a.

From the preceding description, it is evident that a signature S gripped by the infeed jaws 148, 150 on the infeed carriage 128 is transported edgewise past the signature-parting shoe 34 toward the sewing machine saddle 16 during the infeed stroke of the carriage. Mounted in front of the frame plate 174, just ahead of the lower parting shoe guide 170, is a nozzle 182. This nozzle is connected to a source of air (not shown) and is positioned to direct a jet of air against the lower portion of the signature S as the latter approaches the leading end of the lower parting shoe guide 170.

Referring now particularly to FIGS. 9 through 12, it will be observed that during infeed movement-of a signature S with the infeed carriage 128, the signature is held flat against the frame plate 174 by the air jet from the nozzle 182 as the signature approaches the parting shoe 34. As a consequence, the lower protruding portion or lip of the rear signature section enters between the plate and the flange 178 of the lower part ing shoe guide 170. The lower edge of the'front signature section is located slightly above the level of the upper flange edge. Immediately after entering between the-plate and flange, the signature encounters the leading inclined edge of the tapered ramplike flange 176 on the upper signature guide 168. This flange is located to engage the signature a distance above its lower edges and acts to deflect the engaged portions of the signature forwardly away from the frame plate 174. The pro-' jection of the flange forwardly of the plate, at the apex of the flange, is such that the lower edge of the front signature 'section is deflected away from the frame plate to a position slightly forwardly of the lower guide flange 178. The lower edge of the rear signature section, on the other hand, encounters the latter flange and thus remains trapped or caged between this flange and the frame plate. At this point, therefore, the lower edges of the front and rear signature sections are spread apart, as shown in the lower portion of FIG. 10.

The leading end of the parting shoe splitter plate 172 joins the lower parting shoe guide flange 178 immediately following the upper guide flange or ramp 176. The splitter plate is vertically located to enter between the spread lower edges of the front and rear sections of the advancing signature S. This plate inclines forwardly away from the frame plate 174 both in the downward direction and in the direction of infeed movement of the advancing signature. As a consequence, the plate continues the signature spreading or parting action initiated by the parting shoe guide flanges 176, 178. This spreading or parting action of the splitter plate causes the front and rear signature sections to straddle the tapered prow of the sewing ture, as shown in FIG. 5. The signature is then fed into the sewing machine by the reciprocating signature pusher 22, in the manner explained earlier.

The malfunction detector 36 will now be described by reference to FIGS. 5 through 7. This detector comprises an arm 184 disposed in a fore-and-aft plane of the infeed mechanism disposed between and parallel to a pair of supporting plates 186a, 1861; on the infeed frame 44. The front end of the arm is pivotally attached to the upper end of a link 188. The lower end of this link is fixed to a forward pivot shaft 190. Shaft 190 extends parallel to the upper edge of the sewing machine saddle 16 and is rotatably supported at its ends in the frame plates 186a, 1861;. Pivotally joined to the rear end of the arm 184 is a crank arm 192 rigid on a rear rock shaft 194. Shaft 194 extends parallel to shaft 190 and is pivotally supported at its ends in the frame plates 186a, 1861). Also fixed to the rear rock shaft 194 is a crank arm 196. The outer end of this crank arm is connected by a link 198 to a crank arm pro- 20 jection 200 on the lower end of the oscillating carriage drive machine saddle 16 as the signature approaches its terminal arm 138. From this description, it is evident that the malfunction detector arm 184 is oscillated between its full line and broken line positions of FIG. 5 in timed relation to the reciprocating infeed motion of the signature carriage 128. The

.rocking motion of the arm and the infeed motion of the carabout its pivot 204 by a spring 206. Spring 206 is connected between the rear end of the finger 202 and an adjustable bracket 208 secured to the rear end of the arm 184. Bracket 208 is adjustable to locate the finger 202 relative to the arm 184 in the normal position of the finger illustrated in solid lines in FIG. 5. Mounted on the infeed frame .44 adjacent the rear end of the firi ger 202 are a pair of switches 210 and 212,

such as microswitches. Switch 210 is a normally open switch having an actuator which is engaged by an adjustable screw 224 on the rear end of the malfunction detector arm 184 when this arm rocks or rotates to its broken line position of FIG. 5. Engagement of the arm screw 224 with the switch actuator closes the switch 210. Switch 212 has an actuator which is disposed for engagement by the rear end of the malfunction detector finger 202 under the conditions described below. Switch 212 is a normally closed switch which is opened in response to engagement of the detector finger 202 with the switch actuator.

Switches 210 and 212 are connected in electrical series with one another and with a solenoid 214 on the base of the infeed frame 44. Turning to FIGS. 1 and 8, it will be observed that the plunger 216 of the solenoid is connected by a link 218 to one arm of a bellcrank 220 pivotally mounted on the infeed frame 44. The, opposite end of this arm is disposed for engage ment with a clutch'engaging lever 222 on the sewing machine 12. Simultaneous closing of both switches 210 and 212 ener gizes the solenoid 214 to release the lever 222 disengaging the clutch and terminating operation of the sewing machine.

Returning now to FIG. 5, it will be recalled that the malfunction detector arm 184 is rotated from its full line position to its broken line position during the return stroke of the signature infeed carriage 128 and hence immediately after a signature S has been released from the carriage to drop onto the sewing machine saddle 16. Assuming that the signature assumes a proper infeed position on the saddle, forward rotation of the detector arm 184 engages the detector finger 202 with the upper folded edge of the signature on the saddle. The malfunction detector is organized in such a way that this engagement of the detector finger with the folded edge of the signature on the saddle rotates the finger from its normal position a relative to the detector arm, shown in broken lines in FIG. 5, to the intermediate broken line position b of FIG. 5. This rotation of the finger relative to the detector arm locates the rear end of the finger for engagement with the actuator of the switch 212. Under these normal operating conditions, therefore, the switch 210 is closed and the switch 212 is opened upon forward rotation of the malfunction detector arm 184 to its broken line signature-sensing position. The solenoid 214 thus remains deenergized to permit continued operation of the sewing machine 12.

Assume now that the infeed carriage 128, during its infeed stroke, fails to deposit a signature S on the sewing machine saddle 16. Under these conditions, forward rotation of the malfunction detector arm 184 results in movement of the detector finger 202 to its broken line position a in FIG. 5. In other words, the finger remains in its normal position relative to the detector arm when the latter rotates forwardly to its signature-sensing position. In this normal position of the finger relative to the arm, the rear end of the finger is disposed to clear the actuator of the switch 212 when the arm occupies its forward signature-sensing position. It will now be understood, therefore, that rotation of the malfunction detector arm 184 to its forward signature-sensing position under the conditions just stated results in closing of the switch 210 without opening of the switch 212. Accordingly, both switches are closed simultaneously to energize the solenoid 214 and thereby terminate operation of the sewing machine.

Assume next that a signature 8, after release from the infeed carriage 128, fails to drop to its proper position on the sewing machine saddle 16. In this case, the upper folded edge of the signature will be above its normal elevation. Under these conditions, forward rotation of the malfunction detector arm 184 to its broken line signature-sensing position engages the tip of the detector finger 202 with the elevated edge of the improperly placed signature, thereby causing upward rotation of the finger to its upper broken line position c of FIG. 5. In this position, the rear end of the finger 202 is again disposed to clear the actuator of the switch 212 when the detector arm 184 occupies its forward signature-sensing position. As a consequence, sensing operation of the malfunction detector under the conditions just started again results in closing of the switch 210 without opening of the switch 212 to energize the solenoid 214 and terminate operation of the sewing machine.

The operation of the present infeed mechanism is now apparent. Briefly summarizing this operation, the infeed carriage 128 is reciprocated between its signature-receiving and signature-releasing positions in timed relation to the reciprocating motion of the signature pusher 22 on the sewing machine 12. When the carriage is located in its signaturereceiving position, it receives a signature S from the signature hopper 28. The carriage then transports the signature edgewise past the signature parting shoe 34 to a terminal position over the sewing machine saddle 16. The signature is released from the infeed carriage in this terminal position to drop by gravity onto the saddle in straddling relation thereto. During the following return stroke of the infeed carriage, the malfunction detector 36 is operated to sense or detect improper placement of a signature on or absence of a signature from the sewing machine saddle. In the event of either of these malfunctions, the solenoid 214 is energized to terminate operation of the sewing machine 12 and hence the operation of the infeed mechanism 10.

While the invention has been described in what is presently conceived to be one of its most practical embodiments, it will be evident to those versed in the art that various modifications of the invention are possible within the spirit and scope of the following claims.

The inventors claim:

1. The method of feeding signatures each having a folded edge to a book-sewing machine having an infeed saddle of inverted V shape in vertical cross section, which method comprises the steps of:

placing said signatures in a stack with their folded edges at the same side of the stack,

withdrawing said signatures in succession from said stack by gripping each signature along its folded edge, moving each signature following its withdrawal from said stack to a vertical attitude with its folded edge uppermost and then transporting the signature along a direction line parallel to the folded edge of the signature and the apex of said saddle to a terminal position over said saddle,

spreading the center pages of each signature as the latter approaches its terminal position to cause the respective signature to assume an inverted V configuration in its terminal position, and

releasing each signature in its terminal position to drop by gravity onto said saddle.

2. An infeed mechanism for feeding signatures each having a folded edge to a book-sewing machine having an infeed saddle of inverted V shape in vertical cross section, said infeed mechanism comprising:

a frame,

a hopper on said frame for containing a stack of said signatures with their folded edges located at the same side of said hopper,

signature-handling means on said frame for withdrawing said signatures in succession from said stack by gripping each signature along its folded edge, means for moving each signature following its withdrawal to said stack to a vertical attitude with its folded edge uppermost, means for transporting the signature along a direction line parallel to the folded edge of the signature and the apex of said saddle to a terminal position over said saddle, and releasing the signature in its terminal position, and

signature-parting means on said frame in the path of edgewise movement of said signatures to terminal position for spreading the center pages of each signature as the latter approaches said terminal position to cause the signature to assume an inverted V configuration in terminal position, whereby each signature when released in terminal position drops by gravity onto and into straddling relation with said saddle.

3. An infeed mechanism according to claim 2 wherein:

said signature-handling means comprises signature transfer means for withdrawing said signatures in succession from said hopper and infeed means for receiving each signature from said transfer means and transporting the signature edgewise in its vertical attitude to said terminal position, said transfer means and infeed means including signature-gripping means for gripping each signature along its folded edge, and said infeed means including means for releasing said infeed gripping means upon arrival of the signature in terminal position to release the respective signature.

4. An infeed mechanism for feeding signatures each having a folded edge to a book-sewing machine having an infeed saddle of inverted V shape in vertical cross section, said infeed mechanism comprising:

a frame,

a hopper on said frame for containing a stack of said signatures with their folded edges located at the same side of said hopper,

signature-handling means on said frame for withdrawing said signatures in succession from said stack by gripping each signature along its folded edge, transporting the signature edgewise in a vertical attitude to a terminal position over said saddle, and releasing the signature in its terminal position,

signature-parting means on said frame in the path of edgewise movement of said signatures to terminal position for spreading the center pages of each signature as the latter approaches said terminal position to cause the signature to assume an inverted V configuration in terminal position, whereby each signature when released in terminal position drops by gravity onto and into straddling relation with said saddle, and

said signature-handling means comprising an infeed carriage on said frame movable between a signature receiving position adjacent said hopper and a signature-releasing position adjacent said saddle, means for driving said carriage between said receiving and releasing positions,

gripping means on said carriage for gripping each signature along its folded edge in such a way as to support the signature in a vertical attitude parallel to the direction line of movement of said carriage, transfer means for transferring said signatures in succession from said hopper to said carriage gripping means when said carriage occupies said receiving position, said carriage when in signature-releasing position being disposed to locate a.-.

' signature held by said gripping means in said terminal position, means for releasing said carriage gripping means upon arrival of said carriage in said releasing position, and means for operating said transfer means, said releasing means, and said driving means in timed relation.

5. An infeedmechanism according to claim 4 wherein:

said transfer means includes a transfer member movable between a signature-gripping position adjacent said hopper and a signature transfer position adjacent the path of movement of said carriage gripping means, gripping means on said transfer member for gripping each section along its folded edge when. said member occupies said gripping position, said transfer gripping means being movable with said transfer member along a path of motion intersecting said path of motion of said carriage gripping means in such a way that a signature gripped by said transfer, gripping means enters said carriage gripping means during movement of said member from said gripping position to said transfer position with said carriage in said receiving position, and means for driving said transfer member between said gripping and transfer positions in timed relation to movement of said carriage between said receivingand releasing positions in such a way that said transfer member moves to said transfer position immediately following arrival of said carriage in said receiving position to effect transfer of each signature from said transfer gripping means to said carriage gripping means.

6. An infeed mechanism according to claim 5 wherein:

said transfer member is a pivoted arm,

said transfer gripping means are operable between closed gripping positions and open releasing positions, and

means for operating said transfer gripping means between said open and closed positions in timed relation to swinging of said arm in such a way that said transfer gripping means open to receive the folded edge of a signature in said hopper as said arms approach said gripping position and said transfer gripping means close to grip the signature upon arrival of said arm in said gripping position, and said transfer gripping means open to release the signature upon arrival of said transfer arm in said transfer position.

7. An infeed mechanism according to claim 6 including:

pneumatic means adjacent said hopper for deflecting a folded edge of the next signature to be withdrawn from said hopper as said transfer arm approaches said gripping position to locate the folded edge of the latter signature for entry into said transfer arm gripping means.

8. An infeed mechanism for feeding signatures each having a folded edge to a book-sewing machine having an infeed saddle of inverted V shape in vertical cross section, said infeed mechanism comprising:

a frame,

a hopper on said frame for containing a stack of said signatures with their folded edges located at the same side of said hopper,

signature-handling means on said frame for withdrawing said signatures in succession from said stack by gripping each signature along its folded edge, transferring the signature edgewise in a vertical attitude to a terminal position over said saddle and releasing the signature in its terminal position,

said signature-handling means comprising an infeed carriage mounted on said frame for movement between a signature-receiving position adjacent said hopper and a signature-releasing position adjacent said saddle, signature-gripping means on said carriage for gripping each signature along its folded edge in such a way as to support the signature in a vertical attitude parallel to the direction line of movement of said carriage, a signature transfer member supported on said frame adjacent said hopper for movement between a signature-gripping position adjacent said hopper and a signature transfer position adjacent the path of movement of said infeed gripping means, means for driving said infeed carriage and transfer member in timed relation in such a way that said transfer member moves to said transfer position while said infeed carriage occupies said receiving position and said carriage moves to said releasing position during return of said transfer member to said gripping position, means for operating said transfer gripping means in timed relation to movement of said transfer member between said gripping position and said transfer position in such a way that a signature is transferred from said hopper to said carriage gripping means during each stroke of said transfer member from said gripping position to said transfer position, said carriage being thereafter movable to said signature-releasing position, wherein the signature on said carriage is located in said terminal position, and means for releasing said carriage gripping means upon arrival of said carriage in said releasing position to release the signature in terminal position, and

a signature-parting shoe on said frame in the path of edgewise movement of said signatures to terminal position on said carriage for spreading the center pages of each signature as the latter approaches said terminal position to cause the signature to assume an inverted V configuration in its terminal position, whereby each signature when released in said terminal position drops by gravity onto and into straddling relation with said saddle.

9. An infeed mechanism according to claim 8 wherein:

said transfer gripping means comprise spring-loaded gripping jaws on said transfer member which are spring urged to closed position, and

said operating means for said transfer gripping means comprise toggle means for locking said jaws in open position against spring action during movement of said transfer member from said transfer position to said gripping position and releasing said jaws for closing under spring pressure upon arrival of said transfer member in gripping position.

10. An infeed mechanism according to claim 9 wherein:

said gripping jaw operating means further comprises cam means for increasing the spring closing force on said jaws as said transfer member approaches said gripping position and relieving the spring closing force on said gripping jaws during movement of said transfer member from said gripping position to said transfer position.

11. An infeed mechanism for feeding signatures each having a folded edge to a book-sewing machine having an infeed saddle of inverted V shape in vertical cross section, said infeed mechanism comprising:

a frame,

a hopper on said frame for containing a stack of said signatures with their folded edges located at the same side of said hopper, v

signature-handling means on said frame for withdrawing said signatures in succession from said hopper by gripping each signature along its folded edge, transporting the signature edgewise in a vertical attitude to a terminal position over said saddle, and releasing the signature in its terminal position, signature-parting means on said frame in the path of edgewise movement of the signatures to terminal position for spreading the center pages of each signature as the latter approaches said terminal position to cause the signature to assume an inverted V configuration in said terminal position, whereby each signature when released in terminal position drops by gravity onto and into straddling relation with said saddle, and

malfunction detection means for sensing a first malfunction condition involving absence of a signature from said saddle and a second malfunction condition involving improper placement of a signature on said saddle, means controlled by said detector for generating malfunction signals in response to said conditions, means for operating said signature-handling means and said malfunction detector in timed relation in such a way as to render said detector effective to sense said malfunction conditions following each release of a signature in said terminal position, and means controlled by said signals for terminating operation of said infeed mechanism in response to said signals.

12. An infeed mechanism according to claim 11 wherein:

each signature has a proper infeed position on said saddle wherein the folded edge of the respective signature is located at a given elevation over the upper apex of said saddle, and

said malfunction detector includes a finger engageable with the folded edge of each signature on said saddle in such a way that said finger assumes a first position when the signature is properly placed on said saddle, a second position when the signature is improperly placed on said saddle, and a third position in the absence of any signature on said saddle.

13. An infeed mechanism for feeding signatures each having a folded edge to a book-sewing machine having an infeed saddle of inverted V shape in vertical cross section, said infeed mechanism comprising:

a frame,

a hopper on said frame for containing a stack of said signatures with their folded edges located at the same side of said hopper,

signature-handling means on said frame for withdrawing said signatures in succession from said hopper by gripping each signature along its folded edge, transporting the signature edgewise in a vertical attitude to a terminal position over said saddle, and releasing the signature in its terminal position,

signature-parting means on said frame in the path of edgewise movement of said signatures to said terminal positions for spreading the center pages of each signature as the latter approaches said terminal position to cause the signature to assume an inverted V configuration in its terminal position, whereby each signature when released in terminal position drops by gravity onto and into straddling relation with said saddle, and

said signature-parting means comprising a tapered signature-parting shoe disposed in said path and having a pointed leading end adapted for entrance between said center signature pages.

14. An infeed mechanism according to claim 13 including:

means for initially spreading the center pages of each signature as the latter approaches said parting shoe to facilitate entrance of said leading end of said parting shoe between said center pages.

15. An infeed mechanism according to claim 14 wherein:

said initial signature-spreading means comprise pneumatic means.

16. An infeed mechanism according to claim 15 wherein:

each signature has a first group of pages at one side of said center pages and a second group of pages at the opposite side of said center pages, and said first page group is longer than said second page group so as to form a lip along the lower edge of said first page group, and

said pneumatic signature-spreading means comprising means for directing a blast of air against said lip of each signature as the latter approaches said parting shoe so as to deflect said first page group of the respective si nature to one side of said parting shoe and means for de ectmg the other page group of the signature to the opposite side of said parting shoe, whereby the latter enters between said page groups. 

1. The method of feeding signatures each having a folded edge to a book-sewing machine having an infeed saddle of inverted V shape in vertical cross section, which method comprises the steps of: placing said signatures in a stack with their folded edges at the same side of the stack, withdrawing said signatures in succession from said stack by gripping each signature along its folded edge, moving each signature following its withdrawal from said stack to a vertical attitude with its folded edge uppermost and then transporting the signature along a direction line parallel to the folded edge of the signature and the apex of said saddle to a terminal position over said saddle, spreading the center pages of each signature as the latter approaches its terminal position to cause the respective signature to assume an inverted V configuration in its terminal position, and releasing each signature in its terminal position to drop by gravity onto said saddle.
 2. An infeed mechanism for feeding signatures each having a folded edge to a book-sewing machine having an infeed saddle of inverted V shape in vertical cross section, said infeed mechanism comprising: a frame, a hopper on said frame for containing a stack of said signatures with their folded edges located at the same side of said hopper, signature-handling means on said frame for withdrawing said signatures in succession from said stack by gripping each signature along its folded edge, means for moving each signature following its withdrawal to said stack to a vertical attitude with its folded edge uppermost, means for transporting the signature along a direction line parallel to the folded edge of the signature and the apex of said saddle to a terminal position over said saddle, and releasing the signature in its terminal position, and signature-parting means on said frame in the path of edgewise movement of said signatures to terminal position for spreading the center pages of each signature as the latter approaches said terminal position to cause the signature to assume an inverted V configuration in terminal position, whereby each signature when released in terminal position drops by gravity onto and into straddling relation with said saddle.
 3. An infeed mechanism according to claim 2 wherein: said signature-handling means comprises signature transfer means for withdrawing said signatures in succession from said hopper and infeed means for receiving each signature from said transfer means and transporting the signature edgewise in its vertical attitude to said terminal position, said transfer means and infeed means including signature-gripping means for gripping each signature along its folded edge, and said infeed means including means for releasing said infeed gripping means upon arrival of the signature in terminal position to release the respective signature.
 4. An infeed mechanism for feeding signatures each having a folded edge to a book-sewing machine having an infeed saddle of inverted V shape in vertical cross section, said infeed mechanism comprising: a frame, a hopper on said frame for containing a stack of said signatures with their folded edges located at the same side of said hopper, signature-handling means on said frame for withdrawing said signatures in succession from said stack by gripping each signature along its folded edge, transporting the signature edgewise in a vertical attitude to a terminal position over said saddle, and releasing the signature in its terminal position, signature-parting means on said frame in the path of edgewise movement of said signatures to terminal position for spreading the center pages of each signature as the latter apprOaches said terminal position to cause the signature to assume an inverted V configuration in terminal position, whereby each signature when released in terminal position drops by gravity onto and into straddling relation with said saddle, and said signature-handling means comprising an infeed carriage on said frame movable between a signature receiving position adjacent said hopper and a signature-releasing position adjacent said saddle, means for driving said carriage between said receiving and releasing positions, gripping means on said carriage for gripping each signature along its folded edge in such a way as to support the signature in a vertical attitude parallel to the direction line of movement of said carriage, transfer means for transferring said signatures in succession from said hopper to said carriage gripping means when said carriage occupies said receiving position, said carriage when in signature-releasing position being disposed to locate a signature held by said gripping means in said terminal position, means for releasing said carriage gripping means upon arrival of said carriage in said releasing position, and means for operating said transfer means, said releasing means, and said driving means in timed relation.
 5. An infeed mechanism according to claim 4 wherein: said transfer means includes a transfer member movable between a signature-gripping position adjacent said hopper and a signature transfer position adjacent the path of movement of said carriage gripping means, gripping means on said transfer member for gripping each section along its folded edge when said member occupies said gripping position, said transfer gripping means being movable with said transfer member along a path of motion intersecting said path of motion of said carriage gripping means in such a way that a signature gripped by said transfer gripping means enters said carriage gripping means during movement of said member from said gripping position to said transfer position with said carriage in said receiving position, and means for driving said transfer member between said gripping and transfer positions in timed relation to movement of said carriage between said receiving and releasing positions in such a way that said transfer member moves to said transfer position immediately following arrival of said carriage in said receiving position to effect transfer of each signature from said transfer gripping means to said carriage gripping means.
 6. An infeed mechanism according to claim 5 wherein: said transfer member is a pivoted arm, said transfer gripping means are operable between closed gripping positions and open releasing positions, and means for operating said transfer gripping means between said open and closed positions in timed relation to swinging of said arm in such a way that said transfer gripping means open to receive the folded edge of a signature in said hopper as said arms approach said gripping position and said transfer gripping means close to grip the signature upon arrival of said arm in said gripping position, and said transfer gripping means open to release the signature upon arrival of said transfer arm in said transfer position.
 7. An infeed mechanism according to claim 6 including: pneumatic means adjacent said hopper for deflecting a folded edge of the next signature to be withdrawn from said hopper as said transfer arm approaches said gripping position to locate the folded edge of the latter signature for entry into said transfer arm gripping means.
 8. An infeed mechanism for feeding signatures each having a folded edge to a book-sewing machine having an infeed saddle of inverted V shape in vertical cross section, said infeed mechanism comprising: a frame, a hopper on said frame for containing a stack of said signatures with their folded edges located at the same side of said hopper, signature-handling means on said frame for withdrawing said signatures in succession from said sTack by gripping each signature along its folded edge, transferring the signature edgewise in a vertical attitude to a terminal position over said saddle and releasing the signature in its terminal position, said signature-handling means comprising an infeed carriage mounted on said frame for movement between a signature-receiving position adjacent said hopper and a signature-releasing position adjacent said saddle, signature-gripping means on said carriage for gripping each signature along its folded edge in such a way as to support the signature in a vertical attitude parallel to the direction line of movement of said carriage, a signature transfer member supported on said frame adjacent said hopper for movement between a signature-gripping position adjacent said hopper and a signature transfer position adjacent the path of movement of said infeed gripping means, means for driving said infeed carriage and transfer member in timed relation in such a way that said transfer member moves to said transfer position while said infeed carriage occupies said receiving position and said carriage moves to said releasing position during return of said transfer member to said gripping position, means for operating said transfer gripping means in timed relation to movement of said transfer member between said gripping position and said transfer position in such a way that a signature is transferred from said hopper to said carriage gripping means during each stroke of said transfer member from said gripping position to said transfer position, said carriage being thereafter movable to said signature-releasing position, wherein the signature on said carriage is located in said terminal position, and means for releasing said carriage gripping means upon arrival of said carriage in said releasing position to release the signature in terminal position, and a signature-parting shoe on said frame in the path of edgewise movement of said signatures to terminal position on said carriage for spreading the center pages of each signature as the latter approaches said terminal position to cause the signature to assume an inverted V configuration in its terminal position, whereby each signature when released in said terminal position drops by gravity onto and into straddling relation with said saddle.
 9. An infeed mechanism according to claim 8 wherein: said transfer gripping means comprise spring-loaded gripping jaws on said transfer member which are spring urged to closed position, and said operating means for said transfer gripping means comprise toggle means for locking said jaws in open position against spring action during movement of said transfer member from said transfer position to said gripping position and releasing said jaws for closing under spring pressure upon arrival of said transfer member in gripping position.
 10. An infeed mechanism according to claim 9 wherein: said gripping jaw operating means further comprises cam means for increasing the spring closing force on said jaws as said transfer member approaches said gripping position and relieving the spring closing force on said gripping jaws during movement of said transfer member from said gripping position to said transfer position.
 11. An infeed mechanism for feeding signatures each having a folded edge to a book-sewing machine having an infeed saddle of inverted V shape in vertical cross section, said infeed mechanism comprising: a frame, a hopper on said frame for containing a stack of said signatures with their folded edges located at the same side of said hopper, signature-handling means on said frame for withdrawing said signatures in succession from said hopper by gripping each signature along its folded edge, transporting the signature edgewise in a vertical attitude to a terminal position over said saddle, and releasing the signature in its terminal position, signature-parting means on said frame in the path of edgewise movement of the signatures to terminal position for spreading the center pages of each signature as the latter approaches said terminal position to cause the signature to assume an inverted V configuration in said terminal position, whereby each signature when released in terminal position drops by gravity onto and into straddling relation with said saddle, and malfunction detection means for sensing a first malfunction condition involving absence of a signature from said saddle and a second malfunction condition involving improper placement of a signature on said saddle, means controlled by said detector for generating malfunction signals in response to said conditions, means for operating said signature-handling means and said malfunction detector in timed relation in such a way as to render said detector effective to sense said malfunction conditions following each release of a signature in said terminal position, and means controlled by said signals for terminating operation of said infeed mechanism in response to said signals.
 12. An infeed mechanism according to claim 11 wherein: each signature has a proper infeed position on said saddle wherein the folded edge of the respective signature is located at a given elevation over the upper apex of said saddle, and said malfunction detector includes a finger engageable with the folded edge of each signature on said saddle in such a way that said finger assumes a first position when the signature is properly placed on said saddle, a second position when the signature is improperly placed on said saddle, and a third position in the absence of any signature on said saddle.
 13. An infeed mechanism for feeding signatures each having a folded edge to a book-sewing machine having an infeed saddle of inverted V shape in vertical cross section, said infeed mechanism comprising: a frame, a hopper on said frame for containing a stack of said signatures with their folded edges located at the same side of said hopper, signature-handling means on said frame for withdrawing said signatures in succession from said hopper by gripping each signature along its folded edge, transporting the signature edgewise in a vertical attitude to a terminal position over said saddle, and releasing the signature in its terminal position, signature-parting means on said frame in the path of edgewise movement of said signatures to said terminal positions for spreading the center pages of each signature as the latter approaches said terminal position to cause the signature to assume an inverted V configuration in its terminal position, whereby each signature when released in terminal position drops by gravity onto and into straddling relation with said saddle, and said signature-parting means comprising a tapered signature-parting shoe disposed in said path and having a pointed leading end adapted for entrance between said center signature pages.
 14. An infeed mechanism according to claim 13 including: means for initially spreading the center pages of each signature as the latter approaches said parting shoe to facilitate entrance of said leading end of said parting shoe between said center pages.
 15. An infeed mechanism according to claim 14 wherein: said initial signature-spreading means comprise pneumatic means.
 16. An infeed mechanism according to claim 15 wherein: each signature has a first group of pages at one side of said center pages and a second group of pages at the opposite side of said center pages, and said first page group is longer than said second page group so as to form a lip along the lower edge of said first page group, and said pneumatic signature-spreading means comprising means for directing a blast of air against said lip of each signature as the latter approaches said parting shoe so as to deflect said first page group of the respective signature to one side of said parting shoe and means for deflecting the other page group of the signature to the opposite side oF said parting shoe, whereby the latter enters between said page groups. 